Abstract : The growth of single-crystal cadmium telluride by a modified Bridgman technique is being investigated to improve the material for use in infrared modulator devices. This investigation also provides evaluation criteria for use as an infrared window. A systematic variation of selected crystal growth parameters, together with quench and post-growth thermal anneal parameters, is being performed to accomplish this goal. Variation in crucible configuration, utilizing a ball-shaped tip, has shown promise for improved crystallinity of CdTe ingots; all runs using this crucible showed single crystal starts. Installation of a new furnace with increased hot zone promises greater modulator rod yield and longer lengths. Two types of defects - inclusions and random planar (111) imperfections - have been observed in some CdTe crystals. Heat treatment improves absorption properties of crystals with in-grown inclusions, but measured values of absorption coefficient of these crystals do not attain the range of 0.001 to 0.005/cm, typical of material with no initial defects. The technique used for measurement of the electro-optic coefficient is described. (Author)